Sharpener



FIG. 1 is a front-right-top perspective view of a sharpener, showing my new design;

FIG. 2. is a front elevational view thereof;

FIG. 3. is a rear elevational view thereof;

FIG. 4. is a left side elevational view thereof;

FIG. 5. is a right side elevational view thereof;

FIG. 6. is a top plan view thereof; and,

FIG. 7. is a bottom plan view thereof.

The broken lines in FIG. 7 illustrate features of the sharpener that form no part of the claim. 

The ornamental design for a sharpener, as shown and described. 